Improvement in fastenings for safety-valve cases



Patented June 24,1873.

(fimusem I ff. M. I

UNITED STATES GEORGE B. SISSON, OF BUFFALO, NEW YORK.

IMPROVEMENT IN FA'STENINGSFOR SAFETY-VALVE CASES.

Specification forming part of Letters Patent No. 140,223, dated J une24, 1873 application filed February 27, 1873.

In the drawings, Figure 1 is a sectional side elevation. Fig. 2 is asectional front elevationi Fig. 3 is a plan; Figs. 4 and 5, detail viewsof the hasp. v

A is the base or steam-chamber, whose bottom, a, is made with an innerscrew-thread, by which means-it is secured to the boiler. In the top isthe valve-seat b. The interior of chamber A is provided withacross-piece, 0, into the center of which the spindle or guide-rod dot avalve, B, sets, as shown. on

top of the valve B is another spindle or stem,

c, which passes upward through a crosshead or plate, 0, which is securedby'suitable nuts f, g to two upright posts,D D (See Fig. 2.) Surroundingthe stem e, between the crosshead c and valve B, is the usual coiledspring 'E, the whole thus forming the usual spring safety-valve. To makeit a lock-valve, I provide a cover or box,

F,-which sets over the spring and valve, with its. lower edge restingupon the top flange h of the chamber A, as shown, and with au'opening,G, in the top'for the escape ofthe steam, i is a slot or opening throughone side of the flange h, (see Fig. 1,) through which-a gib-hook, 7',passes, which is riveted. tothe side of the box F, the hook-partcatching on the outside of the edge of the flange h, and thus holdingthat side of the case F down. The opposite side of the flange is alsoprovided with a slanting slot, m, through which a tongue or lever-hasp,n, is passed frombeneath, having a slot, '1), in its upper part fittingover a staple, r, secured to the side of they case F, as shown, by whichmeans other important feature of novelty in my invention, as vby thismeans I fasten the case F by only one look, and doing away with hinges,which allows 'the outer case to be removed entirely from place, toreadily reach the valve, &c., for repairs or tests.

In all lock-valves with which 1 am acquainted there is no means ofascertaining whether the valve is in goodorder or not without unlockingthem, or raising the pressore of steam .in the boiler unless it hasreached the point at which the valve is set. The latter is inconvenient,and sometimes dangerous, while the first is only practicable when theinspector is present to unlock it. It is usual to attach to boilers anextra safety-valve for use, in cases of emergency, but this does notobviate the main di-fliculty, which is to ascertain whether thelock-valve is in good order or not.

To accomplish this, I provide. a shaft, H,

which runs across through the top part of the case F, as shown, andwhich is provided with square ends, 8 s, by which means it may be turnedfrom the outside to raise the valve. On the center of this shaft is aforked catch or wiper, I, which catches either side of the top of thevalve-stem 0, above the crosshead (J, the top of. said stem beingprovided'with a head, it. By this means the valve may be operated fromthe outside of the cover, but, at the same time, will not allow it to beheld down, or otherwise tampered with. I thus entirely obviate thegreatest objection to lock-valves, as well as do away with the necessityof an extra'valve,-

as by the use of the shaft or rodH it may be used as a commonsafety-valve without interfering with the lockingpart of it. W is theusual platesuspended over the orifice G to prevent the valve beingreached from In witness whereof I have hereunto signed above. my name inthe presence of two subscribing I claimwitnesses. The gib-hookj, andlocking-hasp n, in com- GEORGE B. SISSON. bination with the case F, andchamber A Witnesses: having the slotted flange h, substantially as J. R.DRAKE,

described, for the purpose specified. O. N. 'WOODWARD.

